The selling in risk assets picked up momentum after the Fed's statement Wednesday, in which it characterized risks to the economy as "significant" and noted that "strains in global financial markets" (or Europe) could be a catalyst. Then overnight, a preliminary China manufacturing data showed moderating growth.

Asked by CNBC if he believed the US risks falling into a double-dip recession , Soror said: "I think we are in it already."

"We have a slowdown and basically a conflict about whether the rich ought to pay taxes to create jobs or not and there was a deal in the making which would have balanced the budget over the long term, but would have allowed short-term fiscal stimulus, which would have been the right policy," Soros said in an interview late Wednesday.

"That was rejected, it fell apart… so it will come to the electorate next year to decide what they want," he added.